I'm a welder, trying to figure out a design for a tandem axle trailer that I have to convert from gooseneck to straight pull. The customer wants to use a heavy pintle hitch(7 ton ?).The trailer frame is made out of 2x8 HSS as well as the gooseneck section that I will be cutting off. I intend to use 3/8x2x6 in an A frame structure, with same material along centre line. The 2x6 will be coped through the front crossmember, and welded to the next crossmember back(4').The "A"sections will be welded directly to front crossmember, and appropriate gussets and fishplates added.Finally, I was thinking to make it stronger, I would run some 2x3 HSS underneath the A sections and extend them from the pintle mount back to the second crossmember. The pintle eye comes adjustable for different vehicle heights. I think this will be set up to pull behind a dumptruck. I was just wondering what height I should be at for the pintle.